Masatoshi Kochi

KRAS mutation leads to decreased expression of regulator of calcineurin 2, resulting in tumor proliferation in colorectal cancer.

KRAS mutations occur in 30–40% of all cases of human colorectal cancer (CRC). However, to date, specific therapeutic agents against KRAS-mutated CRC have not been developed. We previously described the generation of mouse models of colon cancer with and without Kras mutations (CDX2P-G22Cre;Apcflox/flox; LSL-KrasG12D and CDX2P-G22Cre;Apcflox/flox mice, respectively). Here, the two mouse models were compared to identify candidate genes, which may represent novel therapeutic targets or predictive biomarkers. Differentially expressed genes in tumors from the two mouse models were identified using microarray analysis, and their expression was compared by quantitative reverse transcription–PCR (qRT–PCR) and immunohistochemical analyses in mouse tumors and surgical specimens of human CRC, with or without KRAS mutations, respectively. Furthermore, the functions of candidate genes were studied using human CRC cell lines. Microarray analysis of 34 000 transcripts resulted in the identification of 19 candidate genes. qRT–PCR analysis data showed that four of these candidate genes (Clps, Irx5, Bex1 and Rcan2) exhibited decreased expression in the Kras-mutated mouse model. The expression of the regulator of calcineurin 2 (RCAN2) was also observed to be lower in KRAS-mutated human CRC. Moreover, inhibitory function for cancer cell proliferation dependent on calcineurin was indicated with overexpression and short hairpin RNA knockdown of RCAN2 in human CRC cell lines. KRAS mutations in CRC lead to a decrease in RCAN2 expression, resulting in tumor proliferation due to derepression of calcineurin–nuclear factor of activated T cells (NFAT) signaling. Our findings suggest that calcineurin–NFAT signal may represent a novel molecular target for the treatment of KRAS-mutated CRC.

Gasdermin C Is Upregulated by Inactivation of Transforming Growth Factor β Receptor Type II in the Presence of Mutated Apc, Promoting Colorectal Cancer Proliferation

Mutations in TGFBR2, a component of the transforming growth factor (TGF)-β signaling pathway, occur in high-frequency microsatellite instability (MSI-H) colorectal cancer (CRC). In mouse models, Tgfbr2 inactivation in the intestinal epithelium accelerates the development of malignant intestinal tumors in combination with disruption of the Wnt-β-catenin pathway. However, no studies have further identified the genes influenced by TGFBR2 inactivation following disruption of the Wnt-β-catenin pathway. We previously described CDX2P-G19Cre;Apcflox/flox mice, which is stochastically null for Apc in the colon epithelium. In this study, we generated CDX2P-G19Cre;Apcflox/flox;Tgfbr2flox/flox mice, with simultaneous loss of Apc and Tgfbr2. These mice developed tumors, including adenocarcinoma in the proximal colon. We compared gene expression profiles between tumors of the two types of mice using microarray analysis. Our results showed that the expression of the murine homolog of GSDMC was significantly upregulated by 9.25-fold in tumors of CDX2P-G19Cre;Apcflox/flox;Tgfbr2flox/flox mice compared with those of CDX2P-G19Cre;Apcflox/flox mice. We then investigated the role of GSDMC in regulating CRC tumorigenesis. The silencing of GSDMC led to a significant reduction in the proliferation and tumorigenesis of CRC cell lines, whereas the overexpression of GSDMC enhanced cell proliferation. These results suggested that GSDMC functioned as an oncogene, promoting cell proliferation in colorectal carcinogenesis. In conclusion, combined inactivation of both Apc and Tgfbr2 in the colon epithelium of a CRC mouse model promoted development of adenocarcinoma in the proximal colon. Moreover, GSDMC was upregulated by TGFBR2 mutation in CRC and promoted tumor cell proliferation in CRC carcinogenesis, suggesting that GSDMC may be a promising therapeutic target.

possible role of soluble fibrin monomer complex after gastroenterological surgery

AIM To examine the role of soluble fibrin monomer complex (SFMC) in the prediction of hypercoagulable state after gastroenterological surgery. METHODS We collected data on the clinical risk factors and fibrin-related makers from patients who underwent gastroenterological surgery at Hiroshima University Hospital between April 1, 2014 and March 31, 2015. We investigated the clinical significance of SFMC, which is known to reflect the early plasmatic activation of coagulation, in the view of these fibrin related markers. RESULTS A total of 123 patients were included in the present study. There were no patients with symptomatic VTE. Thirty-five (28%) patients received postoperative anticoagulant therapy. In the multivariate analysis, a high SFMC level on POD 1 was independently associated with D-dimer elevation on POD 7 (OR = 4.31, 95%CI: 1.10-18.30, P = 0.03). The cutoff SFMC level was 3.8 μg/mL (AUC = 0.78, sensitivity, 63%, specificity, 89%). The D-dimer level on POD 7 was significantly reduced in high-SFMC patients who received anticoagulant therapy in comparison to high-SFMC patients who did not. CONCLUSION The SFMC on POD 1 strongly predicted the hypercoagulable state after gastroenterological surgery than the clinical risk factors and the other fibrin related markers.

Surgical techniques for advanced transverse colon cancer using the pincer approach of the transverse mesocolon

BackgroundLaparoscopic surgery for colorectal cancer, not only early cancer but also advanced cancer, has become standardized by some randomized controlled studies. However, cases involving advanced transverse colon cancer were excluded from these studies due to the technical difficulty of the surgery. Hence, laparoscopic surgery for advanced transverse colon cancer is still a theme that we need to overcome. To solve these issues, it is necessary to establish a standardized approach and surgical technique.Surgical techniquesThe advantage of our method, which approaches from both sides of the transverse mesocolon, is that it is easier to achieve hemostasis when active bleeding occurs because this approach provides space for ligating and sealing. This allows the surgeon to perform lymphadenectomy around the superior mesenteric artery and vein.ConclusionsWe introduced the usefulness of the “Pincer approach of the transverse mesocolon” to standardize laparoscopic surgery for advanced transverse colon cancer.

A case of ascending colon cancer accompanied with tumor thrombosis in the superior mesenteric vein treated with right hemicolectomy and greater saphenous vein grafting

Highlights • The occurrence of colorectal cancer with tumor thrombosis in the mesenteric vein is very rare.• Complete resection of the primary cancer with tumor thrombosis is essential.• Combined surgery and chemotherapy should be performed to prevent recurrence.

Increased Calcineurin A Expression Is Associated with a Lower Relapse-Free Survival Rate after Colorectal Cancer Surgery

Objective: Increased expression of calcineurin in colorectal cancer (CRC) has been reported. Although the oncogenic function has been suggested, the clinical relevance is still unclear. We herein studied calcineurin expression as a prognostic biomarker in patients receiving curative surgery for stages I-III CRC. Methods: In 121 patients with stages I-III CRC treated at Hiroshima University between 1997 and 2003, calcineurin A expression was examined using immunohistochemistry (IHC) staining of surgical specimens. Specimens were considered positive for calcineurin A if any IHC-stained cells were observed within the carcinomatous area, and clinicopathological characteristics and survival outcomes were compared between IHC-positive and -negative groups. Results: Calcineurin A was preferentially expressed in the cytoplasm of cancer cells, and a median of 8% of the cells (range: 0-80%; interquartile range: 0-22.5%) were stained within the carcinomatous areas. Of 121 cases, 81 were determined as IHC positive while 40 were determined to be negative. Positive expression of calcineurin A, as well UICC-TNM stage, was associated with low relapse-free survival (RFS) rates in multivariate analyses (hazard ratio = 2.92; 95% CI: 1.27-7.92; p = 0.010). Conclusion: Increased calcineurin A expression is associated with lower RFS rates and may have clinical value in predicting recurrence.

Abstract 2303: Impact of synbiotics administration on tumorigenesis of colon cancer mouse model

Introduction: Previous study showed that Synbiotics might have beneficial effect in human and animal colitis like ulcerative colitis. However, it is not well known that the influence of Synbiotics for tumorigenesis in colon cancer. The aim of present study was to investigate the influence of Synbiotics in colon cancer mouse model and colitis associated cancer mouse model. Methods: Mouse stains carrying colon epithelium-preferential Apc mutation (CPC;Apc mice), that show sporadic colorectal adenomas and carcinomas are used in this study. We also used CPC;Apc mice consumed 1%Dextran Sulfate Sodium (DSS) as colitis associated colon cancer model, developing apploximately fourfold more adenomas and adenocarcinomas than CPC;Apc not consumed. At first, 9 of CPC;Apc mice were administerated symbiotics (Probiotics (Lactobacillus) 0.1g + Prebiotics (Oligosaccharide) 10mg/0.3ml/body) between 7 and 20 age in weeks and 10 was not administerated. Secondaly, using 9 of CPC;Apc consumed 1%DSS was administrated Symbiotics, 8 of not administrated, 7 of only Probiotics, and 7 of only Prebiotics. Body weight was measured weekly. Fecal microbial analysis was performed. At sacrifice in 21 age in weeks, the small and large bowel were histologically assessed. Results: Synbiotics administration group has no differences of tumorigenesis comparing to control group (tumor incidence rate(88.9%(8/9) vs. 62.5% (5 / 8); control vs. Synbiotics; p = 0.21)average tumor number(3.2 vs. 2.1; p = 0.38), average tumor greatest diameter 5.8 vs. 5.1 mm; p = 0.51). Using CPC;Apc consumed 1%DSS, Symbiotics administration group showed inhibiting morbidity (50% (8 / 16) vs. 80% (8 / 10); control vs. Synbiotics; p = 0.04) and weight loss, and less tumor incidence than control (18.8 vs. 9.6; control vs. Synbiotics; p = 0.01). On the other hands, administration of probiotics or prebiotics alone had no significant differences of tumorigeneis. Conclusion: This data suggest that Synbiotics administration may have influence of inhibiting tumorigenesis in the colitis associated colon cancer. Citation Format: Yasufumi Saito, Takao Hinoi, Tomohiro Adachi, Manabu Shimomura, Masashi Miguchi, Hiroaki Niitsu, Masatoshi Kochi, Hideki Ohdan, Kazuhiro Sentani, Naohide Oue, Wataru Yasui. Impact of synbiotics administration on tumorigenesis of colon cancer mouse model. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2303. doi:10.1158/1538-7445.AM2015-2303

Abstract 2301: The generation of colorectal cancer mouse model based on microsatellite instability and the identification of transforming growth factor-beta signal target

Background & Aims: The transforming growth factor-beta (TGF-beta) signal is a tumor-suppressor pathway that is commonly inactivated in about 90% of microsatellite instability (MSI) colorectal cancer (CRC). However, there was little evidence what gene is regulated by TGF-beta signal in the multistep progression sequence of CRC. The first aim of the present study was to generate a mouse model that is null for Tgfbr2 and Apc in the colon epithelium and forms tumors in the colon. The second aim was to analyze the tumors that arose in the mice model for the purpose to identify the gene regulated by TGF-beta signal. Method & Result: Previously we have described the generation of the ‘CDX2P-G19Cre;Apcflox/flox mice’ (called Apc KO mice) which is randomly null for Apc in the colonic epithelium. By mating Tgfbr2flox/flox mice with Apcflox/flox and CDX2P9.5-G19Cre mice, we have finally generated a mouse model ‘CDX2P-G19Cre;Apcflox/flox;Tgfbr2flox/flox mice’ (called Apc+Tgfbr2 KO mice) which is null for Apc and Tgfbr2. In these model, the tumors with well differentiated adenocarcinoma arose mainly in proximal colon and most of mice died at 4 weeks age due to tumor bleeding. Therefore the mice were harvested at 3 weeks age to evaluate the development of colon tumors. Total RNAs of only cancerous tissue areas were extracted from frozen samples by the laser capture microdissection method. We compared gene expression profiles of these mice9s tumors (n = 3, respectively) with Mouse Exon 1.0 ST Array (Affymetrix). Gene X expression of Apc+Tgfbr2 KO mice tumors was most highly upregurated by 9.25-fold compared with Apc KO mice (p = 0.045). The array data was validated by quantitative PCR. For human CRC samples, mutations of repetitive mononucleotide tracts in the coding regions of TGFBR2 were identified by direct sequencing. By immunohistochemical analysis, the expression of X was classified according to the percentage of stained cancer cells. The expression was considered to be ‘positive’ if ≥30% of cancer cells were stained. An analysis demonstrated that 11 (100%) of 11 mutated TGFBR2 cases were positive for X, whereas 10 (66.7%) of 15 wild type TGFBR2 cases were positive (P = 0.033), indicating that high expression of X was correlated with TGFBR2 mutation in human CRCs samples. Additionally, the cell proliferation assay revealed that silencing of X led to a significant reduction in CRC cell proliferation. Conversely, forced expression of X enhanced CRC cell proliferation in vitro. Conclusion: We have generated an in vivo model system that Apc and Tgfbr2 were inactivated only in the colonic epithelium and tumors with well differentiated adenocarcinoma arose mainly in proximal colon. The analysis of this model revealed that Gene X is regulated by a TGF-beta signal and likely promotes cell proliferation in CRC. Citation Format: Masashi Miguchi, Takao Hinoi, Manabu Shimomura, Tomohiro Adachi, Yasufumi Saito, Hiroaki Niitsu, Masatoshi Kochi, Yusuke Sotomaru, Hideaki Ijichi, Tsuneo Ikenoue, Kunitoshi Shigeyasu, Kohji Tanakaya, Kazuhiro Sentani, Naohide Oue, Wataru Yasui, Hideki Ohdan. The generation of colorectal cancer mouse model based on microsatellite instability and the identification of transforming growth factor-beta signal target. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2301. doi:10.1158/1538-7445.AM2015-2301